SIM Preference rules for single-modem PepWaves

Product Discussion Pepwave MAX
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I now have my dual SIM (single modem) PepWave Max BR1 Mini operating with two SIMs:

  • Verizon 1GB/$15
  • ATT 15GB/$35
    I’ll mostly be using this in California back roads, where Verizon is usually but not always the best signal. Since I have more GB on ATT, I’d like a setup where the device will default to ATT, but will not get stuck on ATT if the Verizon signal is much better. Since this BR1 Mini only has a single modem, and per How to prioritize Cellular #1 connection over #2 - #9 by MartinLangmaid the search process for switching SIMs can take 3+ minutes, I also want to make sure the connection is not constantly dropping.

Here’s what I’m thinking for settings:

  • SIM: both
  • Preferred: SIM B (ATT)
  • Fallback to Preferred SIM when: Device is idle (30 minutes) or Non-Preferred SIM is connected for 240 minutes

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In my understanding, this means “It’s OK to use the Verizon SIM, but if nobody is using the internet for 30 minutes, OR we’ve been using Verizon for 4 hours, then try again to go back to ATT”.

Questions:

  • What does “Device is Idle” mean? No WiFi connections? WiFi connections, but no data? How is this “idle” defined?
  • I see there is also a “Signal Threshhold” setting:
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How does this work with dual SIMs? If you set a threshold, and both SIMs are below it, will the PepWave be offline? Or will it prefer whichever SIM has better signal?

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Not sure how well device idle works. Because even a cell phone with no apps open and the screen off will still be “active”. I think you need to completely disconnect all client connectivity for it to be truly idle.

Signal threshold is another form of “health check”. I keep mine set to 1 bar.

The measurement is ONLY for the currently ACTIVE SIM. It does not have any way to continuously measure both. Failover between ATT & VZW will take 1-2min for the modem to reset. If the secondary carrier also wont connect I would think after X-number of retries it would flip back to primary.

Also remember that signal strength is no guarantee of “usable bandwidth/performance”

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I tested this in the field this week, and have some more info.

Although I had set the device to prefer SIM B, at one point I realized it was on SIM A. Checking the logs, it was clear that SIM B had failed the Health check at one point, which triggered a switch.

So the logic of which SIM is used is quite complicated as a number of settings can cause a switch:

  • preferred SIM
  • Fallback “Device is idle for ____ minutes”
  • Fallback “Non preferred SIM is connected for _____ minutes”
  • health check
  • Signal threshhold settings

It would be nice if PepLink could give us more info.

Specific questions:

  • How is “Idle” defined? Is it lack of WiFi client connections? Or lack of packets being sent from Client connections?
  • Does the “Signal threshold” setting override other settings? For example, if I have “Prefer SIM B” and “require 2 bars of signal” - what happens if SIM A has 2 bars and SIM B has 1 bar. Which SIM would be used?
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